Commit ccb0e027 authored by Matthew Auld's avatar Matthew Auld
Browse files

drm/i915/ttm: add some sanity checks for lmem_userfault_list 

Rather than getting some hard to debug uaf, add some warns to hopefully
catch issues with userfault_count being non-zero when destroying the
object. Also if we somehow add an object to lmem_userfault_list that
somehow doesn't map lmem.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/7469


Signed-off-by: default avatarMatthew Auld <matthew.auld@intel.com>
Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>
Cc: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: default avatarAndrzej Hajda <andrzej.hajda@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221107165414.56970-2-matthew.auld@intel.com
parent 625b7446

drivers/gpu/drm/i915/gem/i915_gem_ttm.c

+4 −0
Original line number Diff line number Diff line
@@ -1098,6 +1098,8 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf) 
		spin_lock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock);

		list_add(&obj->userfault_link, &to_i915(obj->base.dev)->runtime_pm.lmem_userfault_list);

		spin_unlock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock);



		GEM_WARN_ON(!i915_ttm_cpu_maps_iomem(bo->resource));

	}



	if (wakeref & CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND)
@@ -1180,6 +1182,8 @@ static void i915_ttm_unmap_virtual(struct drm_i915_gem_object *obj) 
		}

	}



	GEM_WARN_ON(obj->userfault_count);



	ttm_bo_unmap_virtual(i915_gem_to_ttm(obj));



	if (wakeref)